1. Technical Field
This invention relates to elevator systems and, more particularly, to a control system for equalizing and directing elevator car usage assignments.
2. Prior Art
Virtually all “Elevator Group Systems” (conventional two button or destination type) of recent invention have been based on “Cost of Service” algorithms (e.g.: Shortest waiting times) using as few elevators in the group as possible, with no regard for equalization of service characteristics or equipment use. The results are lower average service characteristics, (waiting times, trip times, car loading, etc.) but a wide range of individual characteristics. (Some passengers have short waits and trip times while others have long waits and trip times.)
The net result of these designs is also that individual car utilization is disparate. (Elevator Cars often become under-utilized while others are overused.)
In virtually all present systems the passenger destination times, (the sum of waiting+loading+travel times) is the target and is paramount. No effort is made to equalize service to all passengers, equalize use of equipment, minimize total system stops or minimize trip and round-trip times.
Zone/demand assignments, under the SEEDS system, shall be related to the individual car and shall be totally fluid rather than fixed and related to landings.
Accordingly, a need remains for an elevator car usage assignment system to overcome the above-noted shortcomings. The present invention satisfies such a need by providing a destination based elevator group supervisory system designed to equalize service and equipment use. Such a system will minimize the range of system service characteristics to the greatest degree possible and results in shorter average waits, transfer times, trip times, round trip times, and equipment use. As a result, the system will provide greater elevator car availability and optimum demand response.